Apparatus and method for three dimensional manipulation of point of view and object

ABSTRACT

An apparatus and related method permit viewer navigation and object manipulation within a three-dimensional graphical experience or &#34;virtual world&#34; displayed by a programmable digital computer. The apparatus and method include the display of a series of six buttons. Twenty-four operations are divided among the six buttons, with each button having two pairs of cooperating or complementary operations. Three of the buttons are used to accomplish movement of the viewer in relation to the three-dimensional virtual world, and the other three buttons are used to manipulate selected objects within the virtual world. A mouse cursor is used to select one of the buttons and to activate one of four quadrants associated with the selected button to accomplish the operation associated with the activated quadrant. When a button is selected, it expands from its inactivated or &#34;at rest&#34; state to a larger, activated state. Two adjacent quadrants may be activated to perform two operations concurrently. The speed of the movement is directly proportional to the distance of the mouse cursor from a dead zone in the selected button, thereby allowing the user to regulate the movement speed by appropriately positioning the mouse cursor. A software program displays the buttons, determines which of the buttons is activated, and calculates the amount, speed and direction of viewer movement or object manipulation as a function of the position of the mouse cursor.

This application is a continuation of application Ser. No. 08/747,268,filed Nov. 12, 1996, now U.S. Pat. No. 5,874,956, which claims domesticpriority to U.S. provisional application Ser. No. 60/006,544, filed Nov.13, 1995 pending.

FIELD OF THE INVENTION

This invention relates to computers and, more particularly, to asoftware-driven apparatus and related method for-navigating andinteracting with three-dimensional graphics displayed on a monitor by adigital computer.

BACKGROUND OF THE INVENTION

The increasing speed and power of programmable, digital computers suchas desk-top or personal computers, has made computer-generated,real-time, three-dimensional, graphical experiences both accessible andpopular. Such experiences, generally referred to as "virtual reality",allow the personal computer user to navigate through and interact withcomputer-generated, three-dimensional virtual worlds. Such programsallow the user to appear to move about or through a virtual world in anynumber of directions and also allow the user to interact with andmanipulate objects in that world, such as by grabbing selected objects,picking them up, carrying, moving or throwing them.

Navigating through and interacting with three-dimensional virtual worldsis generally accomplished by the user through manipulation of a computerinput device, typically a mouse, to cause the computer program toperform certain movements or manipulations. This approach suffers fromvarious drawbacks and disadvantages. In particular, the cursor of themouse moves across the screen generally in only two dimensions, and suchtwo-dimensional motion generally makes navigating and interacting withthe three-dimensional virtual world not only difficult, but alsocounter-intuitive for the average user. The many possible movementsavailable in the three-dimensional virtual worlds, referred to as"degrees of freedom", are thus not easily or intuitively accessibleusing conventional computer input devices.

Accordingly, there is a need for an apparatus and method which providesintuitive, efficient, and easy-to-use navigation and interaction withinthree-dimensional virtual worlds.

SUMMARY OF THE INVENTION

Therefore an object of this invention is to provide a new and improvedapparatus which permits a digital computer user to navigateor-manipulate objects within a virtual world, and to achieve manydegrees of freedom for such navigation or manipulation.

Another object is to provide a method of programming a digital computerso that it presents a user interface which allows easy and intuitivenavigation and interaction within the three-dimensional virtual world.

According to the present invention, the foregoing and other objects andadvantages are attained by an apparatus which includes a digitalcomputer and an appropriate monitor for displaying a virtual worldgenerated by a computer program running on the digital computer. Part ofthe computer program displays a plurality of buttons which may beselected and manipulated by means of a mouse or other suitable computerinput device.

According to one aspect of the invention, there are six buttonsdisplayed in the apparatus, three of the buttons associated withnavigating through the virtual world and three other buttons associatedwith manipulating objects within the virtual world. When a button isselected, it expands from its inactivated or "at rest" state to alarger, activated state. Each of the buttons in its activated stateincludes a so-called active area surrounding a so-called dead zone.

According to another aspect of the invention, the operations performedby activating the buttons are accomplished more rapidly in proportion tothe distance from the location of the cursor placed within the activearea to the dead zone.

Furthermore, each of the buttons is associated with four distinctoperations which in turn are identified with specific locations on thosebuttons. The cursor may be placed between two of the locations, with theresult that both of the operations associated with the locations oneither side of the cursor are accomplished simultaneously. This canproduce compound operations, such as diagonal movements consisting oftwo separate components simultaneously.

According to still another aspect of the invention, the buttons includetwo complementary or cooperative pairs of operations corresponding totwo degrees of freedom which are frequently linked together when a useractually moves through three-dimensional space. The cooperative pairingof these operations provides an intuitive grouping of operationsavailable on-individual buttons to facilitate complex movement throughor manipulation within a virtual world.

Still other objects, advantages, and novel aspects of the presentinvention will become apparent in the detailed description of theinvention that follows. There, the preferred embodiment of the inventionis shown by the attached drawings illustrating the best mode presentlycontemplated for carrying out the invention, and by describing it withreference to those drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an apparatus according to the presentinvention showing the x, y and z directions of a three-dimensional,virtual world displayed by the apparatus;

FIG. 2 is a front elevational view of a portion of the display of FIG.1, showing six buttons according to the present invention;

FIG. 3 is a front elevational view of the buttons of FIG. 2, with one ofthe buttons activated;

FIGS. 4-8 are front, elevational views of the buttons shown in FIG. 2,each showing a different one of the buttons activated; and

FIGS. 9a-9c are flow charts of a software program for a programmabledigital computer incorporating the principles of the present invention.

DESCRIPTION OF THE INVENTION

In general terms, the present invention involves an apparatus whichincludes a programmable digital computer and a method of programmingsuch digital computer so that a series of buttons is displayed on amonitor of the computer and accessible by a user to navigate through andmanipulate objects in three-dimensional, virtual worlds which aredisplayed on the digital computer. Unlike conventional apparatus andmethods for moving and manipulating within a virtual world, the presentinvention allows the user six degrees of freedom to operate within athree-dimensional virtual world by means of easy-to-use and intuitivebuttons.

Referring now to the drawings, and in particular to FIG. 1, aprogrammable, digital computer 21 runs a computer software applicationprogram which generates any of a variety of three-dimensional, graphicalexperiences (oftentimes referred to as a "virtual world"). In thisparticular embodiment, a real-time, three-dimensional virtual world isdisplayed on a two-dimensional screen 25 of monitor 23 associated withthe computer 21. The three-dimensional image displayed on the screen 25corresponds to the viewpoint of the user within the virtual world. Thisviewpoint will hereinafter be referred to as "the viewer."

Within a three-dimensional, virtual world, there are two fundamentaltypes of operations which may be performed. First, the viewer may bemoved through the virtual world (viewer navigation). For example, theviewer may walk through the room displayed on the screen 25. Second,objects within the virtual world may be manipulated by the user (objectmanipulation). For example, the user may move the base shown on thescreen 25, open or shut one of the windows shown therein, or push thepiano to a new location.

The present invention includes the display of a control pad, bar orwindow 27 which includes therein a series of buttons 31. The window 27may be of any size sufficient to display the buttons and may be in anylocation on the screen 25, such as at the bottom center as shown in thisembodiment, so long as the window 27 does not obscure thethree-dimensional scene or otherwise inhibit operation of the computerprogram. Selective activation of the buttons 31 within the window 27, asdiscussed in detail below, permits the user to engage in both viewernavigation and object manipulation.

Viewer navigation and object manipulation within three-dimensional spacemay each be thought of as involving six degrees of freedom: threetranslational degrees of freedom, and three rotational degrees offreedom. These six degrees of freedom will be described with referenceto the three-dimensional axes 29. Translational movement to the right orto the left of the screen 25 corresponds to movement along the x axis.Translational movement forward or backwards within the three-dimensionalspace of the screen 25 corresponds to movement along the y axis.Movement up or down within the three-dimensional space corresponds tomovement along the z axis.

The three rotational degrees of freedom are as follows: pitching up ordown corresponds to rotation about the x axis, rolling right or leftcorresponds to rotation about the y axis, and yawing right or leftcorresponds to rotation about the z axis.

Translational motion with respect to any of these axes can be in thepositive direction indicated by the arrows of the axes 29 or in thenegative direction away from the arrows corresponding to each of theaxes 29. Likewise, rotation can be in the clockwise or counter-clockwisedirection. Since there are six degrees of freedom and a positive andnegative direction for each of the six degrees of freedom, a total oftwelve operations are possible for viewer navigation and a correspondingtwelve operations for object manipulation, making a total of 24operations which are available within the three-dimensional virtualworlds shown on the screen 25.

Referring now to FIG. 2, the window 27 contains a series of six buttons31.1-31.6. These buttons 31 are displayed by the computer program on thescreen 25 as shown in FIG. 1. Three of these buttons 31.1, 31.2, and31.3 control operations which accomplish navigational movement of theviewer through the three-dimensional, virtual world. These buttons31.1-31.3 are therefore grouped together next to a camera icon 44representing the viewer. The other three buttons 31.4, 31.5, and 31.6perform operations related to object manipulation, and are groupedtogether next to a suitable hand icon 45 indicating object manipulation.

Each button 31 allows the user to have convenient and easy access to allsix degrees of freedom and the twenty-four associated operationsdiscussed above for either viewer navigation or object manipulationwithin the three-dimensional, virtual world. The twenty-four movementoperations discussed above are divided among the six buttons 31, each ofthe buttons being associated with four of the operations. As will beseen in the description below, the four operations associated with eachof the buttons 31 are selected so that each of the buttons 31 includestwo complementary or cooperative pairs of operations. Such cooperativeoperations are then linked to make viewer navigation and objectionmanipulation particularly easy and intuitive for the user.

The buttons 31 are all shown in their inactivated or "at rest" state inFIG. 2. In this state, each of the buttons 31 has four arrows 32disposed thereon, each of which represents one of the operations whichthat particular button 31 may perform. When any one of the buttons 31 isactivated, such as by clicking on it with mouse cursor 19 (FIG. 1), theselected button 31 expands to approximately three times its originallength and width.

The general structure and operation of the buttons 31 will now bediscussed with particular reference to the button 31.1, which is shownin an expanded, activated state in FIG. 3. The button 31.1, when in itsactivated state, includes a central area or dead zone 33, whichcorresponds to the area that was originally taken up by the button 31.1when it was in its inactivated state shown in FIG. 2. The dead zone 33includes dimmed or obscure arrows 32' corresponding to the originalarrows 32 of the button 31.1 when in its "at rest" state. The expansionfeature provides the user with a visual indication of which one of thebuttons 31.1-31.6 has been activated. While the mouse cursor 19 (FIG. 1)remains within the dead area 33 of the button 31.1 (FIG. 3), however,none of the four operations associated with the activated button 31.1 isperformed.

By virtue of the expansion, an active area 35 is created which islocated outside the dotted boundary line 36 of the dead zone 33. Theactive area 35 is divided into four quadrants 37a-d, each of whichcorresponds to one of the operations of the activated button 31.1. Eachof the quadrants 37a-d contains corresponding arrows 39a-d which areconfigured so as to provide a visual indication of the operationscorresponding to the respective quadrants 37a-d.

In the case of the button 31.1, the quadrants 37a and 37b correspond-tomovement of the viewer forward and backward, respectively, along the yaxis within the three-dimensional virtual worlds shown on the screen 25(FIG. 1). The operations of the quadrants 37c and 37d, on the otherhand, yaw the viewer left and right, respectively, by rotation about thez axis (FIG. 1). The pair of operations corresponding to the quadrants37a, 37b, and the pair corresponding to the quadrants 37c, 37dcomplement or cooperate with each other by allowing the viewer to moveforward or backward within the virtual world and also to "look" to theleft or to the right. The two cooperating degrees of freedom associatedwith the quadrants 37a, 37b and 37c, 37d thus simulate the actions of aperson within the virtual world who is walking forward or backwardand/or looking from side-to-side.

The operations of the quadrants 37a-d are accomplished as follows inthis particular embodiment. The button 31.1 is activated selecting itwith the mouse cursor 19. While holding down the selector button of themouse (not shown), the mouse cursor 19 is moved into a selected one ofthe quadrants 37a-d of the button 31.1. For example, if the user movesthe mouse cursor into the quadrant 37a of the button 31.1, then theviewer will start to move forward within the virtual world shown on thescreen 25 (FIG. 1).

As the user moves the mouse cursor 19 farther from the central area ordead zone 33, the operation associated with the quadrant containing thecursor will be accomplished more quickly. The speed of the operation isthus proportional to the distance of the cursor from the boundary 36 ofthe area 33. As an example of this proportional motion, the further themouse cursor is moved from the dead zone 33 within the quadrant 37a, themore quickly the viewer will advance forward along the y axis within thevirtual world.

The active area 35 and the quadrants 37a-d therein are shown with anouter perimeter 41 within the window 27. However, the functionalboundary of the active area 35 and the quadrants 37a-d extends beyondthe perimeter 41 and fills the entirety of the screen 25 (FIG. 1). Inoperation, then, the mouse cursor 19 (FIG. 1) may be dragged beyond theouter perimeter 41 and the operations corresponding to the location ofthe cursor 19 will continue to be performed at a faster and faster rateas the distance from the dead zone 33 increases.

The locations of the quadrants 37a-d in relation to the dead zone 33 areselected to provide the viewer with a further indication of theoperation associated with each of the quadrants. Thus, if the dead zone33 is thought of as the location of the viewer, the quadrant 37a islocated above the dead zone 33, or in front of the viewer. The arrow 39athus points forward of the viewer, so that the quadrant 37a may bereadily associated by the user with movement forward. Conversely, thequadrant 37b and its corresponding backward pointing arrow 39b areassociated with backward movement.

The quadrants 37c and 37d are located to the sides of the viewer, i.e;the dead zone 33, and the arrows 39c and 39d point outwardly and arecurved to convey rotation rather than translation. The quadrants 37c and37d and their associated arrows 39c and 39d thus indicated theoperations of side-to-side movement, comprising positive or negativerotation about the z axis.

The quadrants 37a-d are configured and programmed so that they overlapeach other at diagonal regions 43 of the active area 35. Two adjacentones of the quadrants 37a-d may be activated simultaneously by placingthe mouse cursor in the overlapping diagonal area 43 between thosequadrants. As an example of this simultaneous movement with respect tothe button 31.1, if the user moves the mouse cursor into the diagonalarea 43 which is at the upper right as shown in FIG. 3, then the viewerwill start to move forward (positive translational movement with respectto the y axis of FIG. 1) and will simultaneously yaw to the right(clockwise rotation about the z axis of FIG. 1). In addition, like therest of the active area 35, the diagonal regions 43 extend to fill theentirety of the screen 25, so that faster simultaneous operation can beachieved beyond the boundary 41.

The buttons 31.2-31.6 all operate in a manner similar to that describeabove with reference to the button 31.1. The specific operationsassociated with each of the buttons 31.2-31.6 will now be described withreference to FIGS. 4-8. The button 31.2 is shown in its activated statein FIG. 4. The four operations of the button 31.2 allow the viewer to bedisplaced up or down (that is, by translational movement along the zaxis of (FIG. 1)) and to the left or right (that is, by translationalmovement along the x axis). The active area 35 includes quadrants 47aand 47b which, when activated by the mouse cursor 19 (FIG. 1) accomplishmovement up or down, respectively, along the z axis. Quadrants 47c and47d, when activated by the mouse cursor, accomplish translationalmovement along the x axis.

The quadrants 47a-d are so located in relation to the dead zone 33, andinclude respective appropriately shaped and oriented arrows 49a-d, so asto provide the user with a readily discernable visual indication of thefunction of each of the quadrants 47a-d. In particular, the quadrants47a and 47b are located above and below the dead zone 33, respectively,and the corresponding arrows 49a and 49b are vertically directed andstraight. This arrangement facilitates recognition by the users that theviewer is displaced up or down along the z axis by operation of thequadrants 47a and 47b, respectively. Likewise, the quadrants 47c and 47dare located to either side of the dead zone 33 and are provided withoutwardly directed and straight arrows 49c and 49d, thereby indicatedtranslational, side-to-side movement.

The movement along the x axis alone or the z axis alone may beaccomplished by activating the quadrants 47a-d alone, or such movementsmay be accomplished simultaneously by using diagonal zones as discussedearlier. The four operations of the button 31.2 are selected to providetwo cooperating degrees of freedom. In particular, the viewer may moveleft or right within the image displayed by the screen 25, up or downwithin that image, or diagonally by simultaneously activating adjacentquadrants by means of the diagonal zones. All the operations of thequadrants 47a-d occur without advancing the viewer forward or backwardwithin the virtual world.

The button 31.3 is shown in its activated state in FIG. 5. A first pairof operations associated with the button 31.3 pitch the viewer up ordown with respect to the image of the screen 25; that is, the viewerrotates about the x axis. The second pair of operations associated withthe button 31.3 rolls the view left or right with respect to the imageof the screen 25; that is, the viewer rotates about the y axis. Theactive area 35 of the button 31.3 is divided into quadrants 57a and 57bwhich rotate the viewer up or down about the x axis, respectively, whenthey are activated by the mouse cursor. Similarly, quadrants 57c and 57drotate the viewer counter-clockwise, or clockwise, respectively, aboutthe y axis when they are activated by the mouse cursor.

The quadrants 57a-d are so located in relation to the dead zone 33, andinclude respective appropriately shaped and oriented arrows 59a-d, so asto provide the user with a readily discernable visual indication of thefunction of each of the quadrants 57a-d. In particular, the quadrants57a and 57b are located above and below the dead zone 33, respectively,and the corresponding arrows 59a and 59b are outwardly directed andcurved to indicate rotation. This arrangement facilitates recognition bythe user that the viewer is rotated up or down along the x axis byoperation of the quadrants 57a and 57b respectively. Likewise, thequadrants 57c and 57d are located to either side of the dead zone 33,and are provided with outwardly directed and curved arrows to indicaterotation. This arrangement facilitates recognition by the user that theviewer is rotated counter-clockwise and clockwise about the y axis byoperation of the quadrants 57c and 57d respectively.

The rotations about the x and y axes which are accomplished by thebutton 31.3 create two pairs of operations which result in cooperativedegrees of freedom readily and intuitively understood by the user. Inthe case of the button 31.3, the combination of operations resembles anindividual within the three-dimensional virtual world raising orlowering his or her head or tilting it from side to side.

Referring now to FIGS. 6-8, the buttons 31.4, 31.5, and 31.6 are alsoprovided with the cooperative pairs of translational and rotationaloperations similar to those discussed with reference to the buttons31.1-31.3, except that the buttons 31.4-31.6 operate to manipulateobjects rather than to move or rotate the viewer with respect to thevirtual world. In addition, the same speed-proportionality feature isprovided, even beyond the borders 41.

To use the button 31.4-31.6, then, an object within the virtual world isselected in accordance with the protocols of the computer softwarerunning on the computer 21, and the selected object is then manipulated,such as by moving the object or rotating the object relative to thethree-dimensional space defined by the virtual world.

Rotation of the selected object discussed with reference to buttons31.4-31.6 is described with reference to a set of xyz axes, such asthose shown at 29 (FIG. 1), the zero points (0,0,0) of which are locatedwithin the selected object itself. For object manipulation, therefore,the rotation operations discussed below cause the selected object torotate about one or more axes intersecting the selected object.

Referring to FIG. 6, the button 31.4 is shown in its activated state andcontrols two pairs of cooperative operations similar to those of thebutton 31.1. When the button 31.4 is operated, a selected object may bemoved forward or backward within the three-dimensional virtual world,that is, positive and negative movement along the y axis; or the objectmay be yawed counter-clockwise or clockwise, that is, rotated about a zaxis which extends through the selected object. As with the button 31.1,the button 31.4 includes quadrants 67a-d so located in relation to thedead zone 33, and arrows 69a-d which are appropriately shaped andoriented, so as to indicate to the user the respective operationsassociated with the quadrants 67a-d.

Referring to FIG. 7, the button 31.5 is shown in its activated state andincludes two pairs of cooperative operations for object manipulationsimilar to those of the button 31.2 for viewer navigation. One pair ofoperations for the button 31.5 is used to move a selected object up ordown relative to the space defined by the three-dimensional world, thatis, positive or negative translational movement of the object along thez axis. The second pair of operations accomplishes translationalmovement left or right within the virtual world, that is, positive ornegative movement along the x axis. As with the corresponding button31.2, the button 31.5 includes quadrants 77a-d so located in relation tothe dead zone 33, and arrows 79a-d which are appropriately shaped andoriented, so as to indicate to the user the operation associated withthe quadrants 77a-d.

Referring now to FIG. 8, the button 31.6 is shown in its activated stateand includes two pairs of cooperative operations for object manipulationsimilar to those of the button 31.3 for viewer navigation. One pair ofoperations of the button 31.6 pitches the selected object upward ordownward, that is, rotates the selected object in the positive ornegative direction about an x axis extending through the selectedobject. The other pair of operations available on the button 31.6 rollsa selected object in a counter-clockwise or clockwise direction, thatis, rotates the object in a positive or negative direction about a yaxis extending through the object. As with the corresponding button 31.3for viewer navigation, the button 31.6 includes quadrants 87a-d solocated in relation to the dead zone 33, and arrows 89a-d which areappropriately shaped and oriented so as to indicate to the user theoperation associated with the quadrants 87a-d.

Referring again to FIGS. 1 and 2, the buttons 31.1-31.3 are arrangedinto a first group for viewer navigation, and the buttons 31.4-31.6 arearranged into a second group for object manipulation. Buttons 31.1-31.3are arranged three in a row and the buttons 31.4-31.6 are arranged threein a row in a complementary fashion. That is, the first buttons 31.1 and31.4 of each of the groups accomplish the same two pairs of operationsfor viewer navigation and object manipulation, respectively; the same istrue for the middle buttons 31.2 and 31.5; and the same is true for thelast buttons 31.3 and 31.6.

To operate the apparatus according to the present invention, the windowor bar 27 is called up by a suitable software routine, such as themodule labeled "MAINFRM.CPP" in the microfiche appendix. The userdetermines where he or she wishes to go or which object to manipulate inthe virtual world currently displayed on the screen 25 (FIG. 1). Theuser then selects the appropriate one of the buttons 31.1-31.6.While-holding down the selector button, the user moves the mouse cursor19 into the appropriate quadrant or quadrants of the selected button.The user determines the amount of the movement or manipulation by thetime the mouse cursor is in the quadrant(s). The user determines thespeed of the movement or manipulation by the distance of the mousecursor from the dead zone 33. The process is then repeated as desired bythe user with any of the buttons 31.1-31.6 to further navigate ormanipulate objects within the virtual world.

When the user clicks on one of the buttons 31.1-31.6 to activate it, orreleases the selector button to deactivate the button, a suitablesoftware routine, such as that shown in the module labeled VRMCONTB.CPPin the microfiche appendix, displays the selected button in its expandedstate or returns the selected button to its "at rest" state.

FIGS. 9a-c are a flow chart showing a suitable software program 100according to the present invention for accomplishing the twenty-fourtranslational and rotational operations controlled by the buttons31.1-31.6, which are referred to as buttons #1-#6 respectively in FIGS.9a-c. The software program 100 includes a suitable routine, shown inblock 101, for checking whether the buttons 31.1 or 31.2 have beenactivated. If not activated, another program routine, block 103, checkswhether the buttons 31.3 or 31.4 have been activated. If not, theprogram routine of block 105 checks whether the buttons 31.5 or 31.6have been activated.

If any of the buttons 31.1-31.6 have been activated or "clicked," thebranch labeled "yes" is followed from logic boxes 107. The performanceof the four operations associated with each of the buttons 31.1-31.6 isthen accomplished for the button activated or selected. The performanceof the operations will be described for the button 31.1 referred to as"button #1" in the flow chart of FIG. 9. Performance of the operationsassociated with each of the other buttons 31.2-31.6 is accomplished in asimilar fashion for the buttons #2, #3, #4, #5, and #6, respectively.

When the button 31.1 is activated, a software routine represented byprogram block 109 enlarges the button 31.1 and puts it into itsactivated state as shown in FIG. 3. It will be recalled that the button31.1 moves the viewer either forward or backward along the y axis withinthe three-dimensional virtual world or yaws the view left or right(rotation about the z axis) within the three-dimensional virtual world.The program 100 then checks, in logic box 109, whether the mouse cursoris above the dead zone or area 33 (FIG. 3), that is, in the quadrant 39acorresponding to forward movement along the y axis. If yes, then thedistance between the cursor location and the top of the dead zone 33 iscalculated, as represented by the program block 113. This amount,referred to as the y distance or "Ydist," is used as the basis tocalculate the distance to move the viewer forward as represented by theprogram block 115.

Proportional movement, that is, more rapid movement in proportion toincreased distance from the dead zone 33, is accomplished by multiplyingthe y distance by a movement multiplier indicated as "move.mult" inprogram box 115. The product of the movement multiplier and the ydistance is used in program block 117 to move the viewer along the yaxis by the amount indicated by such product.

Returning to logic box 111, if the cursor is not positioned above thedead zone 33, then the program 100, as represented by the logic box 119,checks whether the cursor is located below the dead zone 33, that is, inthe quadrant 39b corresponding to backward movement along the y axis(FIG. 3). If yes, then, in a manner similar to that discussed forcalculating forward viewer movement, program block 121 determines the ydistance between the cursor location and the bottom of the dead zone 33;and program block 123 multiplies such distance by the appropriatemovement multiplier to accomplish proportional movement. The amount thuscalculated is used to move the viewer backward along the y axis as donein program block 117 discussed previously.

After moving the viewer along the y axis as shown in the program block117, or if the cursor is not located below the dead zone 33, then, asindicated by logic box 125, the software program 100 checks whether themouse cursor is located to the left of the dead zone 33, that is, in thequadrant 39c (FIG. 3). If yes, then the x distance is calculated betweenthe cursor location and the dead zone 33 by program block 127. Havingcalculated the x distance, proportional rotation is calculated inprogram block 129 in a manner similar to that used to calculateproportional movement in the program blocks 115, 123. In the case of theprogram block 129, the angle to yaw the viewer to the left is calculatedand an appropriate rotation multiplier is used to increase the speed ofrotation. The rotation is accomplished by taking the total viewer yawunits calculated in the program block 129 and performing the routinerepresented by program block 131 to yaw the viewer at the appropriatespeed.

Returning to the logic box 125, if the cursor is not located to the leftof the dead zone 33, then, as shown by logic box 133, the softwareprogram 100 checks whether the cursor is located to the right of thedead zone 33, that is, in the quadrant 37d. If yes, then the x distancebetween the cursor location and the dead zone 33 is calculated inprogram block 135. Then the appropriate speed at which to yaw the viewerto the right is calculated in program block 137, and the viewer is yawedat the appropriate rate to the right as shown in the program block 131.

After the viewer is yawed as set out in the program block 131, or if thecursor is not to the right of the dead zone 33, then the softwareprogram 100 checks whether the buttons 31.1 or 31.-2 have been activatedas indicated by the program circle 101 logically connected to theprogram blocks 131, 133.

Simultaneous or near simultaneous performance of two operations of thebutton 31.1 is accomplished by the logical connection of the two programblocks 117, 119 with the logic box 125. In particular, after the viewerhas moved along the y axis as provided by the program block 117, theprogram 100 checks whether the cursor is to the left or to the right ofthe dead zone 33, thus calling for rotation left or right. In this way,when the cursor is displaced from the dead zone 33 both in the ydirection and the x direction, the movement accomplished by the programblock 117 and the yaw accomplished by the program block 131 areperformed in such rapid succession that they appear to the user to beoccurring simultaneously.

The operations of the buttons 31.2-31.6, referred to in FIGS. 9a-c asbuttons #2-6, are accomplished by the software program 100 in the sameway as described with reference to the button 31.1 above. In generalterms, the position of the cursor relative to the dead zone 33 ischecked, the distance from the cursor location to the dead zone iscalculated, the appropriate speed of movement is determined, and theviewer or object is moved and/or rotated accordingly. The softwareroutines for the buttons 31.2-31.6, which correspond to those discussedabove for the button 31.1, are located in areas 201, 301, 401, 501, and601, respectively, of the flow chart.

A suitable example of the program 100 is set out in source code form ina microfiche appendix and identified as module WIRL3VW.CPP.

Alternative embodiments of the present invention may vary the groupingsof operations on the buttons to provide different pairs of cooperativeor complementary operations. Such different pairs of operations may beuseful, for example, to correspond to a particular set of movementsdictated by the "physical" attributes or "laws of nature" of aparticular three-dimensional virtual world.

The viewer navigation buttons and the object manipulations may bedisplayed in alternative formats on the screen 25, or they may bedisplayed in two separate windows or control panels. In furtheralternative embodiments, certain three-dimensional graphical experiencesmay require only a subset of the 24 operations and hence only a subsetof the buttons 31.1-31.6 may be required for such embodiments.

In addition to the advantages apparent from the foregoing description,the invention provides an easy-to-use apparatus and related method fornavigating and manipulating objects within a three-dimensional, virtualworld using a two-dimensional input device, such as a mouse.

Such viewer navigation and object manipulation can be accomplished withthe advantages and flexibility of 24 operations, which cover bothtranslational and rotational movement in all six degrees of freedom.

Although there are 24 available operations, they are grouped among onlysix buttons, rather than the 24 buttons which might otherwise berequired. Such concise grouping means less clutter on the displayscreen, less usage of screen space, less potential confusion for theuser when operating the user interface, and greater ease of operationalong with enhanced intuitiveness.

Indeed, the principles of this invention permit the number of buttons tobe reduced even further. In an alternative embodiment of the invention(which is not illustrated or represented in the program appendix),instead of two sets of three screen buttons each (one for viewernavigation and one for object manipulation as discussed above), there isonly one set of three control buttons, and that set is programmed tofunction alternately as either the viewer navigation controls or theobject manipulation controls, depending on a mode setting. In addition,there is a mode button on screen which is used to toggle that modesetting between viewer navigation and object manipulation. Consequently,in this alternative embodiment of the invention all 24 of the viewernavigation and object manipulation functions may be controlled with agrand total of only three control buttons and one mode button on screen.

A related advantage is that the buttons expand in size only when theyare activated, otherwise remaining at a smaller size. The smaller sizeof the buttons when in their inactive state reduces screen clutter andscreen usage, while still allowing the users to see the location of theinactive buttons and thus allowing ready access to them.

The operations for each of the buttons have been grouped into pairs ofoperations which complement or cooperate with each other to provide theuser with an intuitive combination of motions for each of the buttons.

The buttons according to the present invention have the furtheradvantage of providing proportional motion. The user may thereby adjustthe speed of the operation currently being performed, in contrast to theconventional on/off functionality of the current art, which provides theuser with only one speed for the selected operation.

In addition, the proportionability function is available across theentire screen, thereby giving the user more space to operate, and thusfiner control over, the proportional motion.

The buttons also advantageously allow for simultaneous or compoundmovement by activating two operations of a selected button at the sametime or concurrently.

While the present invention has been described with reference to apreferred embodiment thereof, illustrated in the accompanying drawings,various changes and modifications can be made by those skilled in theart without departing from the spirit and scope of the presentinvention.

The invention claimed is:
 1. In a programmable digital computer having a display, a method comprising:displaying on the display,a three dimensional scene as seen from a point of view and an object; displaying on the display at least a first area that may be selected by a user and a second area that may be selected by the user; and changing the point of view of the scene when the user selects the first area, and moving the object when the user selects the second area.
 2. The method of claim 1, comprising:moving the object forward when a first portion of the second area is selected and moving the object backward when a second portion of the second area is selected.
 3. The method of claim 1, comprising:rotating the object to the left when a first portion of the second area is selected and rotating the object to the right when a second portion of the second area is selected.
 4. The method of claim 1, comprising:moving the object up when a first portion of the second area is selected and moving the object down when a second portion of the second area is selected.
 5. The method of claim 1, comprising:translating the point of view forward when a first portion of first area is selected and translating the point of view backward when a second portion the first area is selected.
 6. The method of claim 1, comprising:rotating the point of view to the right when a first portion of the first area is selected and rotating the point of view to the left when a second portion of the first area is selected.
 7. The method of claim 1, comprising:translating the point of view up when a first portion of the first area is selected and translating the point of view down when a second portion of the first area is selected.
 8. The method of claim 1, comprising:when a first portion of at least one of the areas is selected, performing at least one of, translating the point of view as though the user had rolled to the left, or rolling the object to the left; and when a second portion of at least one of the areas is selected, performing at least one of, translating the point of view as though the view had rolled to the right, or rolling the object to the right.
 9. In a programmable digital computer having a display, a method comprising:displaying on the display,a three dimensional scene as seen from a point of view and an object; displaying on the display at least a first set of buttons that may be selected by a user and a second set of buttons that may be selected by the user; and changing the point of view of the scene when the user selects a button from the first set, and moving the object when the user selects a button from the second set.
 10. The method of claim 9, comprising:the object forward when a first button of second set is selected and moving the object backward when a second button the second set is selected.
 11. The method of claim 9, comprising:rotating the object to the left when a first button of the second set is selected and rotating the object to the right when a second button of the second set is selected.
 12. The method of claim 9, comprising:moving the object up when a first button of the second set is selected and moving the object down when a second button of the second set is selected.
 13. The method of claim 9, comprising:translating the point of view forward when a first button of first set is selected and translating the point of view backward when a second button of the first set is selected.
 14. The method of claim 10, comprising:rotating the point of view to the right when a first button of the first set is selected and rotating the point of view to the left when a second button of the first set is selected.
 15. The method of claim 11, comprising:translating the point of view up when a first button of the first set is selected and translating the point of view down when a second button of the first set is selected.
 16. In a programmable digital computer having a display, a method comprising:displaying on the display,a three dimensional scene as seen from a point of view and an object; displaying on the display at least a first set area that may be selected by a user and an area that may be selected by the user; translating the point of view of the scene left, right, up, down, forward, or backward when the user selects a respective portion of the first area; moving the object left, right, up, down, forward, or backward when the user selects a respective portion of the second area.
 17. The method of claim 16, comprising:rotating the point of view left or right when a respective portion of the first area is selected.
 18. The method of claim 16, comprising:rotating the object left or right when a respective portion of the second area is selected.
 19. The method of claim 16, wherein the first area comprises a first set of buttons and the second area comprises a second set of buttons.
 20. The method of claim 16, comprising:rotating the point of view left or right when a respective portion of the first area is selected. 